Turbine cooling system



July 10, 1962 L. E. VARADI TURBINE COOLING SYSTEM Filed Jan. 28, 1960 &

HOT GASES LOU/5 5. 144mm .United States Patent O 3,043,560 TURBINECOOLING SYSTEM Louis E. Varadi, Danvers, Mass assignor, by mesneassignments, to the United .States of America as represented by theSecretary of the Navy Filed Jan. 28, 1960, Ser. No. 5,312

3 Claims. (Cl. 253-39.15)

The present invention relates to a system for cooling a turbine engineand more particularly to a system for cooling the shaft bearings, wheeland blades of a turbine engine.

One of the most critical problems confronting designers of turbineengines has been providing a system for cooling bearings for the turbineshaft especially those bearings located immediately aft of the turbinewheel.

This has been due to the fact that heat from the hot.

motive gases travels behind the turbine wheel in the area of thebearings and the bearings are not otherwise adequately insulated fromthe hot motive gas chamber. This difficulty has been overcome in thepresent invention by providing a particular structure forming airpassages within the engine thus exposing specific portions of thestructure to cooling air. By this structure the supporting members forthe bearings, the bearings themselves and areas in the vicinity of thebearings are cooled in a novel manner. Also, the present inventionsolves other problems in the art such as cooling the after side of theturbine wheel, the blades mounted thereon, preventing the lubricatingoil and oil mist for the bearings from escaping through a labyrinth sealor packing gland, and further preventing a scavenger oil pump forscavenging the bearing oil from drawing a vacuum on itself.

An object of the present invention is to provide particular cooling air.paths within a turbine enginewhich will more efficiently cool turbinecomponents.

Another object of the present invention is to provide a turbinestructure that will more efficiently prevent the heating ofthe turbineshaft bearings by the hot motive gases.

A further object of the invention is to provide a tur- Y bine structurewith particular cooling air paths which will more efliciently cool theturbine bearings, wheel, and blades, prevent the lubricating oil for thebearings from leaking through packing glands, and prevent the scavengerpump for scavenging oil from drawing a vacuum on itself.

Other objects andmany of the attendant advantages of this invention willbe readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawing wherein:

The single FIGURE of the drawing shows a longitudinal sectional view ofan illustrated embodiment of the invention.-

In the drawing a shaft 2 supported by a roller bearing 3 and a ballbearing 4 has a wheel 5 with blades 6 mounted thereon and extending intothe stream of gases. Circumscn'bing the shaft 2 and the bearings 3 and 4is an inner annular shell 7 having a first forward portion 8 and anafter or rearward portion 9. Forward portion 8 is divided at its innerend into a first annular member 10 directed in a forward direction and asecond annular member 11 directed in an after or rearward directiondefining a first annular area 12. Second annular member 11 has anannular lip 13 which supports the outer race of bearing 3 and afterportion 9 has an annular lip 28 which supports the outer race of bearing4. It is now visualized that shell 7 with its various portions and thebearings define a second annular area 14. This latter area and area 12are to provide chambers for lubricating oil and oil mist for bearings 3and 4. A scavenger oil drain line 15 connected to a pump (not shown)opens into area 14 for scavenging the oil and oil mist. Areas 12 and 14are open to each other through a plurality of openings 27 in member 11and both areas are sealed from the forward part of the engine by alabyrinth seal or packing gland 16 which is mounted on shaft 2 and whichseals against lip 17 of member 10. Circumscribing shell 18 is exposed tohot-motive gases on its outer side and forms an inner casing for,themotive gases within the turbine. Shell 18 is closed at its after orrearward end and having a second forward portion 19 whereby the shelldefines athird annular area 20. Cooling air is introduced into area 20through line 21 which is connected to a compressed air source (notshown). Cooling air leaves area 20 through a plurality of openings 29 inportion 19. Portion 19 and portion 8 with member 10 are locatedpredetermined distance aft of wheel 5 defining an annular area 22. Abafile 23 divides area 22 into a forward annular area 24 and an afterannular area 25. The inner end of baffle 23 is directed forwardly in thevicinity of member 10 forming aforwardly di rected passage 30 betweenthe baffle and member 10.

The end of baifle 23 terminates a predetermined distance from wheel 5maintaining a sufficient pressure within area 26 so that a predeterminedamount of compressed air travels from area 26 into areas 12 and 14through seal 16. The annular baffle area '25 is completely sealed at itsouter end by an extension 31 of shell 18 and annular area 24 is open atits outer end to the hot motive gas chamber.

In the'operation of the illustrated embodiment compressed air from acompressor source (not shown) is introduced into the third annular area20 through line 21 after which it travels through openings 29 intoannular baffie area 25. The area 20 acts as a buffer between the intenseheat in the hot gas chamber and area 14 and the flowing through openings29 cools member 19 thus causing member 19 to act as a dam preventingheat flow from the hot metal shell 18 throughthe portion 8 and member 11to bearing 3. From area 25 the air travels into area 26 in which latterarea it splits into two separate air flows, one being outwardly fromarea 26 into area 24 and the other leaking through seal 16 into thefirst and second annular areas 12 and 14. The air fiow into area 24cools the Wheel '5 and blades 6 after which it passes into the hotmotive gas stream thus preventing hot gases from entering area 24. Theother air flow directly cools the lubrication oil and oil mist in areas12 and 14 and directly cools the bearings 3 and 4 and thereafter exitsarea 14 through line 15 which is connected to a scavenger pump (notshown). It will be noted that not only does the air leak from area 26into areas 12 and 14 prevent oil leaking through the seal 16 into area26 but this air within area 14 will prevent the scavenger pump (notshown) which is connected to line 15 from drawing a vacuum on itself.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. In a turbine engine having a shaft, a turbine wheel mounted on oneend of the shaft, and blades mounted on the wheel, a device for coolingthe turbine engine comprising a forward mounted bearing and an aftermounted bearing for said shaft, a first annular shell defining a firstannular area between the forward mounted bearing and a portion of theshaft between the forward mounted bearing and the wheel for containing alubricant, a second annular shell circumscribing said shaft andconnecting the first annular shell and the after mounted bearingformleast one opening into the second annular area, and an outlet fromsaid second annular area whereby a coohng I gas enters said inlet,passes'through the third annular area, then passes to the forward bafilearea where a predetermined portion of the cooling gas flows to the wheeland :blades and the remaining portion of the cooling gas passes throughthe labyrinth seal into the first annular area to cool the bearing andto combine with oil therein to form a mist which passes into the secondannular chamber to effect cooling and lubrication of the forward andafter mounted bearings before passing out of the system through saidoutlet. 7 V p 2. In a jet engine having a shaft, bearings mounted on theforward and rearward portions of said shaft, a turbine wheel mountedonone end of said shaft for rotation therewith, a plurality of bladesmounted on the periphery of said whee1,'a device for cooling saidturbine wheel and bearings comprising a first annular shell circumscrib-.ingsaid forward mounted bearing and forming a first annular area, asecond annular shell circumscribing said shaft from said first annularshell to said rearward mountedbearing forming a second annular areatherebetween, a third annular shell circumscribing said second annularshell forming a third annular area, a forward baffle plate locatedintermediate said turbine wheel and the forward end of said shells, saidbaflie plate extending radially inward toward said shaft forming abaffie area, inlet means to said third annular shell, outlet means fromsaid second annular shell, meansinterconnecting said third annular areato'said baflie area, means for interconnecting said ,baffle area to saidfirst annular area, means interconnecting said first annular area tosaid second annular area whereby said cooling gases flow through saidinlet means to said outlet means thus eifecting cooling of said turbinewheehbladesand bearings. I

3. In a'jet engine having a shaft, a first and second bearing mounted onthe forward and after portions of said shaft, respectively, said firstand second bearings rotatably supporting said shaft, a turbine wheelmounted on said shaft, a plurality of blades fixedly secured to saidturbine wheel, an improved system for cooling said wheel and bearingscomprising a first radial wall located downstream from said turbineWheel and extending radially outward from said forward bearing, a secondwall extending radially outward from said rearward bearing, said firstwall having a first and second portion immediately adjacent said forwardbearing forming a first annular area, inlet and outlet means from saidfirst annular area, a first annular shell concentric with said shaft andbeing secured to said first and second walls at its forward and rearwardends, respectively, said first annular shell cooperating with said firstand second walls to form a second annular area, said outlet means fromsaid first annular area also serving as the inlet of said second annulararea, outlet means from said second annular area, a second annular shellconcentric with said first annular shell and located radially outwardtherefrom, said second annular shell being secured to said first andsecond radial walls at the outermost ends of said radial walls forming athird annular area, inlet means in said second annular shell leading tosaid third annular area, outlet means in said first radial wallinterconnecting said third annular area with the area between said firstradial wall and the downstream side of said wheel, an annular hafliefixedly secured to the forwardmost end of said second annular shell andextending radially inward toward said first portion of said first wallwhereby relatively cool gas enters said third annular. area, passesthrough said first radial wall and passes radially inward between saidbaflle and said first radial wall, at the innermost end of said bafflesaid gases take two diverse paths, one path being radially outwardimmediately forward of said baflie to cool said turbine wheel, the otherpath being through said first annular area thus cooling said forwardmounted bearing thence into said second annular area further coolingsaid forward bearing and permitting said rearward mounted bearing. andsaid shaft to be cooled by said gases flowing therethrough.

References Cited in the file of this patent UNITED STATES PATENTSGreenwald Feb. 28,

